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基于机器学习和未来气候变化模式的埃塞俄比亚粮食产量预测 被引量:2
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作者 徐宁 李发东 +7 位作者 张秋英 艾治频 冷佩芳 舒旺 田超 李兆 陈刚 乔云峰 《中国生态农业学报(中英文)》 CAS CSCD 北大核心 2024年第3期490-504,I0001,I0002,共17页
对于以农业产业为支柱的埃塞俄比亚,粮食供应和安全对国家安全和人民的生计尤为重要。由于作物生长和气候因素之间的复杂耦合关系,预测气候变化对农作物产量影响具有较大难度,机器学习技术为这种复杂系统变化的预测提供了一种有效途径... 对于以农业产业为支柱的埃塞俄比亚,粮食供应和安全对国家安全和人民的生计尤为重要。由于作物生长和气候因素之间的复杂耦合关系,预测气候变化对农作物产量影响具有较大难度,机器学习技术为这种复杂系统变化的预测提供了一种有效途径。本研究利用37个全球气候模式(GCM)的数据以及土壤数据,基于机器学习模型,预测了埃塞俄比亚2021年至2050年5种主要粮食作物在SSP1-2.6、SSP2-4.5和SSP5-8.5情景下的产量变化。经GCM和变量的筛选后,利用梅赫季和贝尔格季中5种主要粮食作物的10个产量数据对直方图梯度提升决策树、极端梯度提升随机森林、轻梯度提升决策树、随机森林、极限树以及K近邻6种机器学习模型进行训练。经过模型评估,选择表现良好的3个模型,采用线性回归算法进行堆叠,然后使用堆叠模型进行预测。研究结果表明,未来30年埃塞俄比亚梅赫季5种主要粮食作物产量变化以增产<2 t·hm^(-2)为主;SSP126情景下的贝尔格季将出现更明显的减产现象,这可能是由于温室效应的减缓降低了CO_(2)的施肥效应。随着人类活动造成的生态环境恶化,研究区农业生产对粮食结构改变和重新分配生产力的需求不断增长,导致农作物生产力向新的适宜地区转移。研究区在SSP126和SSP585情景下将分别因为干旱缓解和温室效应加剧而获得更高的粮食作物生产力。 展开更多
关键词 粮食产量 机器学习 气候变化 全球气候模式 埃塞俄比亚
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Ti、Zr和Hf元素协同优化Nb-Si基合金显微组织、相组成和室温断裂韧性
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作者 王琪 赵天宇 +4 位作者 陈瑞润 王晓伟 徐琴 王墅 傅恒志 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第1期194-202,共9页
采用真空电弧熔炼制备Nb-16Si-xTi-yZr-zHf (x=18, 22;y=0, 4;z=0, 4;摩尔分数,%)合金并研究Ti、Zr与Hf元素对Nb-Si合金物相组成、显微组织、断裂韧性以及裂纹扩展行为的影响。结果表明:单独添加4%Zr元素能促进(Nb,X)3Si向Nb固溶体(Nbs... 采用真空电弧熔炼制备Nb-16Si-xTi-yZr-zHf (x=18, 22;y=0, 4;z=0, 4;摩尔分数,%)合金并研究Ti、Zr与Hf元素对Nb-Si合金物相组成、显微组织、断裂韧性以及裂纹扩展行为的影响。结果表明:单独添加4%Zr元素能促进(Nb,X)3Si向Nb固溶体(Nbss)/γ-(Nb,X)5Si3共析反应的发生;同时添加Ti、Zr、Hf元素能进一步促进共析反应的发生。裂纹倾向于在(Nb,X)3Si中扩展,当裂纹途径Nb固溶体时会发生偏转。细密的Nbss/γ-(Nb,X)5Si3共晶组织以及层状Nbss/γ-(Nb,X)5Si3共晶组织可以使裂纹产生桥接与分支,阻碍裂纹的扩展。Nb-16Si-22Ti-4Zr-4Hf的合金化元素含量最高,因此,其室温断裂韧性最好(11.62 MPa·m1/2),相较于Nb-16Si-18Ti提高87.7%,性能的提升主要归因于存在层状共晶组织。 展开更多
关键词 Nb-Si合金 合金化 断裂韧性 裂纹扩展
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Towards complex scenes: A deep learning-based camouflaged people detection method for snapshot multispectral images
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作者 shu wang Dawei Zeng +3 位作者 Yixuan Xu Gonghan Yang Feng Huang Liqiong Chen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第4期269-281,共13页
Camouflaged people are extremely expert in actively concealing themselves by effectively utilizing cover and the surrounding environment. Despite advancements in optical detection capabilities through imaging systems,... Camouflaged people are extremely expert in actively concealing themselves by effectively utilizing cover and the surrounding environment. Despite advancements in optical detection capabilities through imaging systems, including spectral, polarization, and infrared technologies, there is still a lack of effective real-time method for accurately detecting small-size and high-efficient camouflaged people in complex real-world scenes. Here, this study proposes a snapshot multispectral image-based camouflaged detection model, multispectral YOLO(MS-YOLO), which utilizes the SPD-Conv and Sim AM modules to effectively represent targets and suppress background interference by exploiting the spatial-spectral target information. Besides, the study constructs the first real-shot multispectral camouflaged people dataset(MSCPD), which encompasses diverse scenes, target scales, and attitudes. To minimize information redundancy, MS-YOLO selects an optimal subset of 12 bands with strong feature representation and minimal inter-band correlation as input. Through experiments on the MSCPD, MS-YOLO achieves a mean Average Precision of 94.31% and real-time detection at 65 frames per second, which confirms the effectiveness and efficiency of our method in detecting camouflaged people in various typical desert and forest scenes. Our approach offers valuable support to improve the perception capabilities of unmanned aerial vehicles in detecting enemy forces and rescuing personnel in battlefield. 展开更多
关键词 Camouflaged people detection Snapshot multispectral imaging Optimal band selection MS-YOLO Complex remote sensing scenes
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Mid-infrared Period-Luminosity Relations of Gaia DR3 Long Period Variables
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作者 Xiaohan Chen Xiaodian Chen +2 位作者 Licai Deng shu wang Tianlu Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第7期56-70,共15页
Long period variable(LPV)stars are very promising distance indicators in the infrared bands.We selected asymptotic giant branch(AGB)stars in the Large and Small Magellanic Cloud(LMC and SMC)from the Gaia Data Release ... Long period variable(LPV)stars are very promising distance indicators in the infrared bands.We selected asymptotic giant branch(AGB)stars in the Large and Small Magellanic Cloud(LMC and SMC)from the Gaia Data Release 3 LPV catalog,and classified them into oxygen-rich(O-rich)and carbon-rich(C-rich)AGB stars.Using the Wide-field Infrared Survey Explorer database,we determined the W1-and W2-band period-luminosity relations(PLRs)for each pulsation-mode sequence of AGB stars.The dispersion of the PLRs of O-rich AGB stars in sequences C'and C is relatively small,around 0.14 mag.The PLRs of LMC and SMC are consistent in each sequence.In the W2 band,the PLR of large-amplitude C-rich AGB stars is steeper than that of small-amplitude C-rich AGB stars,due to their more circumstellar dust.By two methods,we find that some PLR sequences of O-rich AGB stars in the LMC are dependent on metallicity.The coefficients of the metallicity effect areβ=-0.533±0.213 mag dex~1andβ=-0.767±0.158 mag dex~1for sequence C in W1 and W2 bands,respectively.The significance of the metallicity effect in W1 band for the four sequences is 2.2-3.5σ.Both of these imply that distance measurements using O-rich Mira may need to take the metallicity effect into account. 展开更多
关键词 STARS VARIABLES general-stars distances-infrared STARS
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Memristive feature and mechanism induced by laser-doping in defect-free 2D semiconductor materials
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作者 Xiaoshan Du shu wang +11 位作者 Qiaoxuan Zhang Shengyao Chen Fengyou Yang Zhenzhou Liu Zhengwei Fan Lijun Ma Lei wang Lena Du Zhongchang wang Cong wang Bing Chen Qian Liu 《Journal of Semiconductors》 EI CAS CSCD 2024年第7期85-91,共7页
Memristors as non-volatile memory devices have gained numerous attentions owing to their advantages in storage,in-memory computing, synaptic applications, etc. In recent years, two-dimensional(2D) materials with moder... Memristors as non-volatile memory devices have gained numerous attentions owing to their advantages in storage,in-memory computing, synaptic applications, etc. In recent years, two-dimensional(2D) materials with moderate defects have been discovered to exist memristive feature. However, it is very difficult to obtain moderate defect degree in 2D materials, and studied on modulation means and mechanism becomes urgent and essential. In this work, we realized memristive feature with a bipolar switching and a configurable on/off ratio in a two-terminal MoS_(2) device(on/off ratio ~100), for the first time, from absent to present using laser-modulation to few-layer defect-free MoS_(2)(about 10 layers), and its retention time in both high resistance state and low resistance state can reach 2×10^(4) s. The mechanism of the laser-induced memristive feature has been cleared by dynamic Monte Carlo simulations and first-principles calculations. Furthermore, we verified the universality of the laser-modulation by investigating other 2D materials of TMDs. Our work will open a route to modulate and optimize the performance of 2D semiconductor memristive devices. 展开更多
关键词 2D-material memristor laser doping laser direct writing memristive mechanism
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THE GLOBAL EXISTENCE AND UNIQUENESS OF SMOOTH SOLUTIONS TO A FLUID-PARTICLE INTERACTION MODEL IN THE FLOWING REGIME
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作者 Lin ZHENG shu wang 《Acta Mathematica Scientia》 SCIE CSCD 2024年第5期1877-1885,共9页
This paper is concerned with the Cauchy problem for a 3D fluid-particle interaction model in the so-called flowing regime inℝ3.Under the smallness assumption on both the external potential and the initial perturbation... This paper is concerned with the Cauchy problem for a 3D fluid-particle interaction model in the so-called flowing regime inℝ3.Under the smallness assumption on both the external potential and the initial perturbation of the stationary solution in some Sobolev spaces,the existence and uniqueness of global smooth solutions in H3 of the system are established by using the careful energy method. 展开更多
关键词 fluid-particle flowing regime global existence
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The Impact of Varied Fertilizers on the Yield and Quality of Panicum miliaceum under Low Nitrogen Conditions
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作者 Mengyao wang Jiao Mao +6 位作者 Yuanmeng Xu shu wang Yuhan Liu Jiangling Ren Sichen Liu Zhijun Qiao Xiaoning Cao 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第10期2629-2644,共16页
To clarify the response characteristics of broomcorn millet yield and quality to various fertilizers under low nitrogen conditions,the present study investigated the effects of different fertilization treatments,inclu... To clarify the response characteristics of broomcorn millet yield and quality to various fertilizers under low nitrogen conditions,the present study investigated the effects of different fertilization treatments,including no fertilization(HCK,CCK),urea(HF1,CF1),phosphate fertilizer(HF2,CF2),compound fertilizer(HF3,CF3),and organic fertilizer(HF4,CF4),on the agronomic traits,quality,and starch pasting properties of proso millet.As experimental materials,non-waxy proso millet(Hequ red proso millet,denoted as HQH)and waxy proso millet(Chishu 1,denoted as CS1)were utilized.The results showed that under low nitrogen conditions,urea treatment(HF1)significantly increased plant height and yield,and phosphate fertilizer treatment(HF2)significantly increased thousand-grain weight(TW).For waxy proso millet Chishu NO.1(CS1),urea treatment(CF1)significantly increased yield,phosphate fertilizer treatment(CF2)significantly influenced the height of the plants,and compound fertilizer treatment(CF3)significantly increased thousand-grain weight.In terms of quality,phosphate fertilizer treatment(CF2)and organic fertilizer treatment(CF4)resulted in a substantial augmentation of both the total starch content and amylose content of waxy proso millet Chishu NO.1(CS1),respectively,and organic fertilizer treatment(HF4,CF4)resulted in a notable enhancement of the protein content of proso millet.Organic fertilizer treatment(HF4)increased peak viscosity(PV),hot viscosity(HV),setback viscosity(SV),final viscosity(FV),breakdown viscosity(BV),pasting time(PTim),and pasting temperature(PTemp)of non-waxy proso millet.Phosphate fertilizer treatment(CF2)increased the peak viscosity(PV),hot viscosity(HV),breakdown viscosity(BV),final viscosity(FV),pasting time(PTim),and pasting temperature(PTemp)of waxy proso millet.Organic fertilizer treatment(HF4)and phosphate fertilizer treatment(CF2)under low nitrogen were the most effective in improving the comprehensive quality of non-waxy and waxy proso millet,respectively.The findings of our research elucidated the impacts of various fertilizers on the productivity and quality of non-waxy and waxy proso millet in nitrogen-deficient environments.Furthermore,this research offered a conceptual underpinning for attaining enhanced cultivation outcomes,encompassing both improved yield and quality,of proso millet in drought-prone regions. 展开更多
关键词 Proso millet low nitrogen YIELD QUALITY
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Mental health and insomnia problems in healthcare workers after the COVID-19 pandemic:A multicenter cross-sectional study
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作者 Wei Ding Min-Zhong wang +8 位作者 Xian-Wei Zeng Zhen-Hua Liu Yao Meng Hui-Ting Hu Yuan Zhang Yu-Guang Guan Fan-Gang Meng Jian-Guo Zhang shu wang 《World Journal of Psychiatry》 SCIE 2024年第5期704-714,共11页
BACKGROUND Healthcare workers(HCWs)are at increased risk of contracting coronavirus disease 2019(COVID-19)as well as worsening mental health problems and insomnia.These problems can persist for a long period,even afte... BACKGROUND Healthcare workers(HCWs)are at increased risk of contracting coronavirus disease 2019(COVID-19)as well as worsening mental health problems and insomnia.These problems can persist for a long period,even after the pandemic.However,less is known about this topic.AIM To analyze mental health,insomnia problems,and their influencing factors in HCWs after the COVID-19 pandemic.METHODS This multicenter cross-sectional,hospital-based study was conducted from June 1,2023 to June 30,2023,which was a half-year after the end of the COVID-19 emergency.Region-stratified population-based cluster sampling was applied at the provincial level for Chinese HCWs.Symptoms such as anxiety,depression,and insomnia were evaluated by the Generalized Anxiety Disorder-7,Patient Health Questionnaire-9,and Insomnia Severity Index.Factors influencing the symptoms were identified by multivariable logistic regression.RESULTS A total of 2000 participants were invited,for a response rate of 70.6%.A total of 1412 HCWs[618(43.8%)doctors,583(41.3%)nurses and 211(14.9%)nonfrontline],254(18.0%),231(16.4%),and 289(20.5%)had symptoms of anxiety,depression,and insomnia,respectively;severe symptoms were found in 58(4.1%),49(3.5%),and 111(7.9%)of the participants.Nurses,female sex,and hospitalization for COVID-19 were risk factors for anxiety,depression,and insomnia symptoms;moreover,death from family or friends was a risk factor for insomnia symptoms.During the COVID-19 outbreak,most[1086(76.9%)]of the participating HCWs received psychological interventions,while nearly all[994(70.4%)]of them had received public psychological education.Only 102(7.2%)of the HCWs received individual counseling from COVID-19.CONCLUSION Although the mental health and sleep problems of HCWs were relieved after the COVID-19 pandemic,they still faced challenges and greater risks than did the general population.Identifying risk factors would help in providing targeted interventions.In addition,although a major proportion of HCWs have received public psychological education,individual interventions are still insufficient. 展开更多
关键词 COVID-19 Mental health Psychological symptoms INSOMNIA Sleep disorders Cross-sectional study Epidemiological study
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Unraveling the complexities of adolescent depression:A call for action
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作者 Yuan Zhang Ming-Yan Hei +2 位作者 Min-Zhong wang Jian-Guo Zhang shu wang 《World Journal of Psychiatry》 SCIE 2024年第11期1772-1778,共7页
The adolescent years are a period of profound change,both physically and psychologically.For many,these years are marked by excitement and exploration,but for others,they are fraught with challenges that can lead to s... The adolescent years are a period of profound change,both physically and psychologically.For many,these years are marked by excitement and exploration,but for others,they are fraught with challenges that can lead to significant mental health issues.Depression,in particular,has become an increasingly prevalent concern among adolescents worldwide,and its multifaceted etiology requires a comprehensive approach to understanding and intervention.A recent study on the relationships among negative life events,dysfunctional attitudes,social support,and depressive symptoms in Chinese adolescents offers valuable insights into the complex interplay between various factors contributing to adolescent depression.The authors explore a moderated mediation model to better understand how these factors interact with and contribute to the onset of depression.This article aims to delve into the key findings of the study,highlight its implications for clinical practice,and encourage further research in this critical area. 展开更多
关键词 DEPRESSION ADOLESCENT Mental health Dysfunctional attitudes Social support Negative life events
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Impact of transcranial electrical stimulation on serum neurotrophic factors and language function in patients with speech disorders
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作者 Li Sun Kai Xiao +1 位作者 Xiao-Yan Shen shu wang 《World Journal of Clinical Cases》 SCIE 2024年第10期1742-1749,共8页
BACKGROUND Speech disorders have a substantial impact on communication abilities and quality of life.Traditional treatments such as speech and psychological therapies frequently demonstrate limited effectiveness and p... BACKGROUND Speech disorders have a substantial impact on communication abilities and quality of life.Traditional treatments such as speech and psychological therapies frequently demonstrate limited effectiveness and patient compliance.Transcranial electrical stimulation(TES)has emerged as a promising non-invasive treatment to improve neurological functions.However,its effectiveness in enhancing language functions and serum neurofactor levels in individuals with speech disorders requires further investigation.AIM To investigate the impact of TES in conjunction with standard therapies on serum neurotrophic factor levels and language function in patients with speech disorders.METHODS In a controlled study spanning from March 2019 to November 2021,81 patients with speech disorders were divided into a control group(n=40)receiving standard speech stimulation and psychological intervention,and an observation group(n=41)receiving additional TES.The study assessed serum levels of ciliary neurotrophic factor(CNTF),glial cell-derived neurotrophic factor(GDNF),brainderived neurotrophic factor(BDNF),and nerve growth factor(NGF),as well as evaluations of motor function,language function,and development quotient scores.RESULTS After 3 wk of intervention,the observation group exhibited significantly higher serum levels of CNTF,GDNF,BDNF,and NGF compared to the control group.Moreover,improvements were noted in motor function,cognitive function,language skills,physical abilities,and overall development quotient scores.It is worth mentioning that the observation group also displayed superior perfor CONCLUSION This retrospective study concluded that TES combined with traditional speech and psychotherapy can effectively increase the levels of neurokines in the blood and enhance language function in patients with speech disorders.These results provide a promising avenue for integrating TES into standard treatment methods for speech disorders. 展开更多
关键词 Transcranial electrical stimulation Serum neurofactor levels Developmental level Language features
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Circulating CCRR serves as potential novel biomarker for predicting acute myocardial infarction
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作者 Lina Xuan Huishan Luo +14 位作者 shu wang Guangze wang Xingmei Yang Jun Chen Jianjun Guo Xiaomeng Duan Xiufang Li Hua Yang Shengjie wang Hailong Zhang Qingqing Zhang shulei Liu Yongtao She Kai Kang Lihua Sun 《Frigid Zone Medicine》 2024年第3期137-151,共15页
Objective:Cold regions exhibit a high prevalence of cardiovascular disease,particularly acute myocardial infarction(AMI),which is one of the leading causes of death associated with cardiovascular conditions.Cardiovasc... Objective:Cold regions exhibit a high prevalence of cardiovascular disease,particularly acute myocardial infarction(AMI),which is one of the leading causes of death associated with cardiovascular conditions.Cardiovascular disease is closely linked to the abnormal expression of long non-coding RNA(lncRNA).This study investigates whether circulating levels of lncRNA cardiac conduction regulatory RNA(CCRR)could serve as a biomarker for AMI.Materials and methods:We measured circulating CCRR from whole blood samples collected from 68 AMI patients and 69 non-AMI subjects.An AMI model was established using C57BL/6 mice.Quantitative reverse transcription PCR(qRT-PCR)was used to assess CCRR expression.Exosomes were isolated from cardiomyocytes,and their characteristics were evaluated using electron microscope and nanoparticle tracking analysis.The exosome inhibitor GW4869 was employed to examine the effect of exosomal CCRR on cardiac function using echocardiography.Protein expression was detected using Western blot and immunofluorescence staining.Results:The circulating level of CCRR was significantly higher in AMI patients(1.93±0.13)than in non-AMI subjects(1.00±0.05,P<0.001).The area under the ROC curve(AUC)of circulating CCRR was 0.821.Similar changes in circulating CCRR levels were consistently observed in an AMI mouse model.Exosomal CCRR derived from hypoxia-induced cardiomyocytes and cardiac tissue after AMI were increased,a change that was reversed by GW4869.Additionally,CCRR-overexpressing exosomes improved cardiac function in AMI.Conclusion:Circulating lncRNA CCRR is a potential predictor of AMI.Exosomal CCRR plays a role in the communication between the heart and other organs through circulation. 展开更多
关键词 acute myocardial infarction lncRNA cardiac conduction regulatory RNA EXOSOME
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Large-conductance Ca^2+-activated K^+ channel involvement in suppression of cerebral ischemia/reperfusion injury after electroacupuncture at Shuigou(GV26) acupoint in rats 被引量:9
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作者 Yong wang Yan Shen +3 位作者 Hai-ping Lin Zhuo Li Ying-ying Chen shu wang 《Neural Regeneration Research》 SCIE CAS CSCD 2016年第6期957-962,共6页
Excess activation and expression of large-conductance Ca^2+-activated K^+ channels(BKCa channels) may be an important mechanism for delayed neuronal death after cerebral ischemia/reperfusion injury. Electroacupunc... Excess activation and expression of large-conductance Ca^2+-activated K^+ channels(BKCa channels) may be an important mechanism for delayed neuronal death after cerebral ischemia/reperfusion injury. Electroacupuncture can regulate BKCa channels after cerebral ischemia/reperfusion injury, but the precise mechanism remains unclear. In this study, we established a rat model of cerebral ischemia/reperfusion injury. Model rats received electroacupuncture of 1 m A and 2 Hz at Shuigou(GV26) for 10 minutes, once every 12 hours for a total of six times in 72 hours. We found that in cerebral ischemia/reperfusion injury rats, ischemic changes in the cerebral cortex were mitigated after electroacupuncture. Moreover, BKCa channel protein and m RNA expression were reduced in the cerebral cortex and neurological function noticeably improved. These changes did not occur after electroacupuncture at a non-acupoint(5 mm lateral to the left side of Shuigou). Thus, our findings indicate that electroacupuncture at Shuigou improves neurological function in rats following cerebral ischemia/reperfusion injury, and may be associated with down-regulation of BKCa channel protein and m RNA expression. Additionally, our results suggest that the Shuigou acupoint has functional specificity. 展开更多
关键词 acupoint suppression cortex neurological minutes neuronal conductance involvement unclear RNA
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典型城市河流硝态氮污染来源的氮氧同位素解析
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作者 国秋艳 张秋英 +4 位作者 舒旺 柏杨巍 李兆 卫毅梅 刘丹妮 《环境工程技术学报》 CAS CSCD 北大核心 2023年第5期1820-1828,共9页
城市河流硝态氮(NO_(3)^(-)N)污染已经成为快速城市化发展中备受关注的水环境问题。以西安市皂河为例,于2021年的5月(旱季)和9月(雨季)采集其河流水体、排口出水和污水处理厂进出水,测定水质参数,并利用氮氧稳定同位素和Iso Source模型... 城市河流硝态氮(NO_(3)^(-)N)污染已经成为快速城市化发展中备受关注的水环境问题。以西安市皂河为例,于2021年的5月(旱季)和9月(雨季)采集其河流水体、排口出水和污水处理厂进出水,测定水质参数,并利用氮氧稳定同位素和Iso Source模型解析NO_(3)^(-)N来源。结果表明:5月和9月皂河NO_(3)^(-)N的δ^(15)N分别为-26.43‰~32.29‰和-2.81‰~20.85‰,δ^(18)O分别为-23.42‰~53.02‰和-5.26‰~21.53‰;粪污是皂河NO_(3)^(-)N的主要来源,皂河不同污染源NO_(3)^(-)N来源的平均贡献率,河流水体为粪污>土壤中氮>化肥>大气沉降,排口出水为粪污>土壤中氮>化肥>大气沉降,污水处理厂进水为大气沉降>粪污>土壤中氮>化肥,污水处理厂出水为粪污>土壤中氮>化肥>大气沉降;土壤中氮和粪污合计对皂河流域NO_(3)^(-)N的贡献率大于70%。控制居民生活污水排放、加强管网建设、强化畜禽粪污管理以及加强土地施肥监督等,有利于减轻城市河流NO_(3)^(-)N污染。 展开更多
关键词 城市河流 硝态氮(NO3-N) 水化学 氮氧同位素 IsoSource模型
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A progressive surrogate gradient learning for memristive spiking neural network
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作者 王姝 陈涛 +4 位作者 龚钰 孙帆 申思远 段书凯 王丽丹 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期689-697,共9页
In recent years, spiking neural networks(SNNs) have received increasing attention of research in the field of artificial intelligence due to their high biological plausibility, low energy consumption, and abundant spa... In recent years, spiking neural networks(SNNs) have received increasing attention of research in the field of artificial intelligence due to their high biological plausibility, low energy consumption, and abundant spatio-temporal information.However, the non-differential spike activity makes SNNs more difficult to train in supervised training. Most existing methods focusing on introducing an approximated derivative to replace it, while they are often based on static surrogate functions. In this paper, we propose a progressive surrogate gradient learning for backpropagation of SNNs, which is able to approximate the step function gradually and to reduce information loss. Furthermore, memristor cross arrays are used for speeding up calculation and reducing system energy consumption for their hardware advantage. The proposed algorithm is evaluated on both static and neuromorphic datasets using fully connected and convolutional network architecture, and the experimental results indicate that our approach has a high performance compared with previous research. 展开更多
关键词 spiking neural network surrogate gradient supervised learning memristor cross array
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Existence of Approximate Solutions for Modified Poisson Nernst-Planck Describing Ion Flow in Cell Membranes 被引量:2
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作者 Abidha Monica Gwecho shu wang Onyango Thomas Mboya 《American Journal of Computational Mathematics》 2020年第3期473-484,共12页
Dynamics of ions in biological ion channels has been classically analyzed using several types of Poisson-Nernst Planck (PNP) equations. However, due to complex interaction between individual ions and ions with the cha... Dynamics of ions in biological ion channels has been classically analyzed using several types of Poisson-Nernst Planck (PNP) equations. However, due to complex interaction between individual ions and ions with the channel walls, minimal incorporation of these interaction factors in the models to describe the flow phenomena accurately has been done. In this paper, we aim at formulating a modified PNP equation which constitutes finite size effects to capture ions interactions in the channel using Lennard Jonnes (LJ) potential theory. Particularly, the study examines existence and uniqueness of the approximate analytical solutions of the mPNP equations, First, by obtaining the priori energy estimate and providing solution bounds, and finally constructing the approximate solutions and establishing its convergence in a finite dimensional subspace in <em>L</em><sup>2</sup>, the approximate solution of the linearized mPNP equations was found to converge to the analytical solution, hence proof of existence. 展开更多
关键词 Lennard Jonnes Potential Finite Size Effects Ion Channel Modified PNP
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Acupuncture for stroke cohort construction:a protocol describing a multicenter,prospective,real-world cohort construction study
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作者 Gui-Ping Li shu wang +6 位作者 Fan Xu Lin-Na Wu Chen Yang Hao-Long Guo Li Li Sha Yang Hui-Yan Shi 《TMR Non-Drug Therapy》 2023年第1期14-21,共8页
Background:Acupuncture for stroke has been endorsed by the World Health Organization,and the Chinese Guidelines for the Diagnosis and Treatment of Acute Ischemic Stroke 2018 lists acupuncture for stroke as a Level II ... Background:Acupuncture for stroke has been endorsed by the World Health Organization,and the Chinese Guidelines for the Diagnosis and Treatment of Acute Ischemic Stroke 2018 lists acupuncture for stroke as a Level II recommendation with Level B evidence.The efficacy of acupuncture in the treatment of acute ischaemic stroke needs to be approved by more high-quality studies.However,there are currently no real-world studies of acupuncture for stroke.Methods:Stroke patients who meet the study criteria and are hospitalized from February 2021 to March 2022 in 23 medical institutions across China,including the First Teaching Hospital of Tianjin University of Chinese Medicine.The number of patients planned to be recruited is 3,000.Due to the impact of COVID-19,we have applied to the competent authorities for an extension(recruit patients until December 2022).Basic patient information and treatment information will be registered at admission,at discharge,and on the following dates after the onset of the disease:90±7 days,180±7 days,and 360±7 days after the onset of the disease.Establish a database for statistical analysis.Discussion:This study proposes to conduct a prospective cohort study of acupuncture intervention for stroke in a real-world medical setting.Analysis of the effect pattern of acupuncture intervention on the recovery of neurological function system and swallowing disorder in stroke patients.Evaluate the long-term effects of acupuncture intervention for stroke and recurrence of cardiovascular and cerebrovascular events. 展开更多
关键词 STROKE ACUPUNCTURE cohort studies real-world MULTICENTER
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土地利用结构与景观格局对鄱阳湖流域赣江水质的影响 被引量:40
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作者 徐启渝 王鹏 +3 位作者 王涛 舒旺 张华 齐述华 《湖泊科学》 EI CAS CSCD 北大核心 2020年第4期1008-1019,共12页
于2015年1月和7月采集赣江干流及支流34个采样点水样,测定电导率、水化学离子、无机氮等水质指标.利用赣江流域2014年30 m分辨率的土地利用数据,以流域景观类型占比表征土地利用结构,景观指数表征景观格局;采用Pearson相关分析、Bioenv... 于2015年1月和7月采集赣江干流及支流34个采样点水样,测定电导率、水化学离子、无机氮等水质指标.利用赣江流域2014年30 m分辨率的土地利用数据,以流域景观类型占比表征土地利用结构,景观指数表征景观格局;采用Pearson相关分析、Bioenv分析、Mantle检验与方差分解等方法分析流域土地利用结构与景观格局对赣江水质的影响.结果表明:上游Cl-、Na+浓度最高,中游电导率、Cl-、Na+、K+、Ca2+等水质指标最低,下游电导率、HCO3-、SO42-、Mg2+、Ca2+、NO3--N等水质指标最高.居民建设用地是对水质影响最显著的单一土地利用类型.林地、水田与居民建设用地是对水质影响最显著的土地利用类型组合.平均最近邻体指数是对水质影响最显著的单一景观指数,斑块个数、斑块聚集度指数、平均最近邻体指数是对水质影响最显著的景观指数组合.枯水期土地利用结构和景观格局对水质的贡献率分别为41.1%和17.2%,景观格局对水质的贡献率(17.2%)均为和土地利用结构的交互作用,无独立贡献部分;丰水期二者对水质贡献率分别为51%、53%,交互作用部分为37%.以上结果表明,土地利用结构与景观格局都对赣江水质有较大影响,二者的交互作用在该影响中占有重要地位,且枯水期景观格局对水质的影响涵盖在与土地利用结构的交互作用中. 展开更多
关键词 赣江流域 土地利用 景观指数 水质 交互作用
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袁河流域土地利用方式对河流水体碳、氮、磷的影响 被引量:21
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作者 黄益平 王鹏 +4 位作者 徐启渝 舒旺 丁明军 张华 曾婷 《环境科学研究》 CAS CSCD 北大核心 2021年第9期2132-2142,共11页
为探明土地利用方式对袁河水体碳、氮、磷浓度的影响,于2018年8月(丰水期)和2019年1月(枯水期)在袁河干流和支流38个采样点采集水样并测定碳、氮、磷(DOC、NO_(3)^(-)-N、NH_(4)^(+)-N和TP)浓度.将流域划分为子流域和沿河岸不同距离(100... 为探明土地利用方式对袁河水体碳、氮、磷浓度的影响,于2018年8月(丰水期)和2019年1月(枯水期)在袁河干流和支流38个采样点采集水样并测定碳、氮、磷(DOC、NO_(3)^(-)-N、NH_(4)^(+)-N和TP)浓度.将流域划分为子流域和沿河岸不同距离(100、200、300、400、500、1000和2000 m)缓冲区,结合Pearson相关性分析、冗余分析(redundancy analysis,RDA)和回归分析等方法,量化不同尺度土地利用方式对干支流碳、氮、磷浓度的影响.结果表明:①建设用地、农田、水域是袁河水体碳、氮、磷浓度的主要影响因素,其中建设用地对NH_(4)^(+)-N、DOC和TP浓度影响最大,水域、农田分别对NO_(3)^(-)-N、DOC浓度影响较大.②土地利用方式对干流碳、氮、磷浓度变化的解释量大于支流,丰、枯水期对干流碳、氮、磷浓度变化的解释量分别为47.2%、36.7%,对支流的解释量分别为23.2%、26.4%.③土地利用方式对干流DOC浓度变化的解释量在丰水期低于对TP、NH_(4)^(+)-N和NO_(3)^(-)-N浓度变化的解释量,在枯水期高于对TP、NH_(4)^(+)-N和NO_(3)^(-)-N浓度变化的解释量;土地利用方式对支流DOC浓度变化的解释量在丰、枯水期均高于对TP、NH_(4)^(+)-N和NO_(3)^(-)-N浓度变化的解释量.④缓冲区尺度土地利用方式对河流碳、氮、磷浓度的影响大于子流域尺度,且干流缓冲区大于支流缓冲区.随缓冲区尺度增加,土地利用方式对水体碳、氮、磷浓度变化的解释能力在干流丰水期和支流枯水期均先增后降,在干流枯水期和支流丰水期的解释能力逐渐增强.研究显示,加强缓冲区土地利用方式的管理,特别是对干流建设用地点源污染和支流农田面源污染的控制,是袁河水环境管理的关键. 展开更多
关键词 袁河 土地利用 碳、氮、磷 缓冲区
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水保措施对柑橘果园土壤细菌群落结构的影响 被引量:6
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作者 吴波波 王鹏 +4 位作者 肖胜生 余小芳 舒旺 张华 丁明军 《环境科学研究》 EI CAS CSCD 北大核心 2021年第2期419-430,共12页
为探索水保措施对柑橘果园土壤细菌群落结构的影响,以江西省德安县柑橘果园为研究对象,选取4种水保措施〔狗牙根条带覆盖(TD)、狗牙根全园覆盖(QY)、经济作物萝卜-大豆轮作条带覆盖(LZ)和净耕果园(JG)〕,基于高通量测序技术确定了柑橘... 为探索水保措施对柑橘果园土壤细菌群落结构的影响,以江西省德安县柑橘果园为研究对象,选取4种水保措施〔狗牙根条带覆盖(TD)、狗牙根全园覆盖(QY)、经济作物萝卜-大豆轮作条带覆盖(LZ)和净耕果园(JG)〕,基于高通量测序技术确定了柑橘果园土壤不同土层〔表层(0~10 cm)、中层(10~20 cm)、底层(20~40 cm)〕的细菌群落结构,并采用PLS-DA分析和冗余分析(RDA)等统计方法研究了不同水保措施条件下柑橘果园细菌群落结构特征及差异.结果表明:①与JG相比,TD、QY和LZ各层土壤中的全氮(TN)、土壤有机碳(SOC)和土壤有机质(SOM)含量均有提高,尤其是QY提高明显,其3层土壤中的平均TN、SOC和SOM含量分别提高了近50%、40.33%和40.26%.②与JG相比,QY表层土壤的细菌丰度显著增加了近1.51倍,且不同水保措施下QY表层和TD中底层土壤的Shannon-Wiener指数分别最高.③柑橘果园土壤中主要细菌门有Chloroflexi(28.39%~45.32%)、Acidobacteria(13.20%~23.31%)、Proteobacteria(14.65%~22.95%)和Actinobacteria(7.20%~11.26%).与TD、QY和LZ相比,JG土壤中Chloroflexi的相对丰度较高,Acidobacteria和Proteobacteria的相对丰度较低.除Chloroflexi相对丰度增加外,不同水保措施下Proteobacteria和Actinobacteria的相对丰度均沿剖面深度呈减少趋势;不同水保措施下Acidobacteria的相对丰度亦沿剖面深度呈减少趋势,但TD除外.④不同水保措施下土壤细菌群落差异显著,TN、SOC和SOM(尤其是TN)是主要影响因素.⑤网络分析表明,Proteobacteria是4种水保措施下土壤细菌交互作用的核心细菌;QY土壤细菌群落交互作用网络的稳定性优于TD、LZ和JG.研究显示,水保措施可以通过改变土壤理化环境来影响细菌群落结构,TD、QY和LZ均提高了土壤中的TN、SOC和SOM含量,增加了土壤细菌多样性,其中以QY的提高最为显著,且土壤细菌群落交互作用的稳定性最好. 展开更多
关键词 水保措施 高通量测序 土壤细菌 群落结构 多样性
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袁河水系溶解态痕量金属元素分布特征及来源分析 被引量:3
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作者 曾婷 王鹏 +3 位作者 舒旺 张华 丁明军 黄高翔 《环境化学》 CAS CSCD 北大核心 2021年第2期583-591,共9页
为研究袁河水系水体溶解态痕量金属元素污染来源与水质状况,分别于2018年7月和2019年1月在袁河干流和支流采集38个表层水样,检测了痕量金属元素Cr、Fe、Mn、As、Al、Cd、Ni和Tl的浓度.采用单因素方差分析分析袁河水系痕量金属元素的时... 为研究袁河水系水体溶解态痕量金属元素污染来源与水质状况,分别于2018年7月和2019年1月在袁河干流和支流采集38个表层水样,检测了痕量金属元素Cr、Fe、Mn、As、Al、Cd、Ni和Tl的浓度.采用单因素方差分析分析袁河水系痕量金属元素的时空特征,基于痕量金属元素水质指数评价袁河痕量金属元素污染程度,采用相关分析、主成分分析探讨痕量金属元素污染的主要来源.结果表明,袁河部分金属元素时间或空间差异显著,Cr、Cd、As浓度在丰、枯水期之间差异显著,Fe、Cd、Tl浓度在干、支流之间差异显著.袁河丰、枯水期污染程度相似,主要污染河段位于宜春河段和新余河段,重度污染采样点基本上位于支流.痕量金属元素中Cr、Fe、As主要来源于城市废水,工业活动和采矿活动;Ni、Cd、Tl主要来源于生活污水和工业废水;Mn、Al主要来源于自然活动和采矿活动.本研究可以为袁河流域的痕量金属元素污染治理提供科学依据. 展开更多
关键词 袁河水系 溶解态痕量金属元素 分布特征 来源分析 污染评价
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